Database error 12500 at con

Hello All,

I am getting the following error message in the SM21 system logs. The users are getting disconnected whilst working on SAP.

Error message is:

14:24:28 BTC 19 BY2 Database error 12500 at CON

14:24:28 BTC 19 BY0 > ORA-12500: TNS:listener failed to start a dedicated server

14:24:28 BTC 19 BY0 > process

14:24:28 BTC 19 R19 Initialization DB-Connect Failed, Return Code 000256

I am using ECC 5.0 with Kernal 640 patch level 170, databse Oracle 9.2.0.8,

Please let me know, how to proceed to stop this message.

Thanks,

Kalyan.